WinDirStat

The disk analyzer to use where licenses matter. WinDirStat is open source, works offline and shows no ads, and its colored treemap still makes oversized folders obvious at a glance. For years it was the slow option, essentially frozen since the mid-2000s. The 2.x rewrite that began in 2024 changed that, and version 2.5 added direct scanning of the NTFS Master File Table, the same trick that made WizTree's name, plus a dark mode. If you dismissed it a decade ago, it is worth a second look.